1. Field of the Invention
The present invention relates to a temperature detection device for detecting temperature.
2. Description of the Related Art
In recent years, along with downsizing and higher circuit integration in mobile communication devices and the like, more devices are apt to generate much heat. A well-known example of means to protect circuits from such heat is overheat protection means for suspending the circuit operation when a predetermined temperature is detected (see, for example, Japanese Patent Application Laid-open No. Hei 7-13643).
A well-known example of a temperature detection device for detecting a predetermined temperature is the one in which an output of a temperature sensor for outputting a voltage corresponding to temperature and a reference voltage are compared and the magnitude relation therebetween is determined by a comparator (see, for example, Japanese Patent Application Laid-open No. 2003-108241).
FIG. 6 is a configuration diagram illustrating a conventional temperature detection device. The conventional temperature detection device includes a temperature sensor 601, a reference voltage circuit 602, and a comparator 603. A voltage of the reference voltage circuit 602 is constant with respect to temperature, and is set to a voltage that the temperature sensor 601 outputs at a temperature to be detected. The comparator 603 outputs the magnitude relation between a voltage of the temperature sensor 601 and the voltage of the reference voltage circuit 602. The temperature detection device is configured to indicate whether or not the temperature has reached the temperature to be detected based on the output of the comparator 603.
Mobile communication devices are required to operate with low consumption in order to extend the battery duration. It is therefore desired that current consumption of individual parts be smaller. In the conventional temperature detection device, however, an operating current flows all the time, and hence there is a problem that the current consumption of the temperature detection device increases.